What is energy?

1. What is energy? Ability to do work

2. What are oxidation-reduction reactions? • Chemical reactions in which there is a transfer of electron(s) from one reactant to another. Molecules receiving an electron are reduced and those donating an electron are oxidized.

3. What are the Laws of Thermodynamics? • 1st Law – energy can not be created nor destroyed – it can only be converted – and when it is – heat is given off • 2nd Law – disorder in the universe is a continual process. Entropy

4. What is “free energy”? • The energy available to do work in a system – G is the symbol for free energy

5. What is activation energy? • The amount of energy needed to help start a chemical reaction. Enzymes help to lower the activation energy required.

6. What are enzymes? • Biological catalysts that help to lower activation energy and speed up chemical reactions.

7. How does temperature, pH, inhibitors, activators, and coenzymes affect enzymatic activity? • Temperature – can render an enzyme inactive. Too hot – denatures enzyme – too flexible. Too cold – enzyme is too rigid and can not flex around substrate. • pH can dissociate the ions and cause an enzyme to degrade rendering it inactive. • Inhibitors – competitive – blocks active site. Non-competitive (allosteric) distant site • Activators – speed up enzymes • Coenzymes – non-organic cofactors that help transfer electrons during a chemical reaction

8. What is ATP? • Adenosine tri-phosphate – is a high energy molecule used to help power biological systems. ATP has two high energy bonds (7.3 kcal)

9. What is a biochemical pathway? • A serious of sequential steps involving more than one enzyme acting on the substrate and resulting in a final product which can release a by-product that has an affect on the first enzyme in the chain and can shut down the pathway – feedback inhibition.

10. When an atom or molecule gains one or more electrons, it is said to bereduced

11. Reactions that do NOT proceed spontaneously because they require energy from an outside source are calledendergonic

12. In an enzyme catalyzed reaction, the reactant (being acted upon) is called thesubstrate

13. Enzymes are very specific in their choices of substrates, because each different enzyme has an active site thatis shaped to fit a certain substrate molecule

14. ATP gives up energy when it is converted to ADP & phosphate

15. Enzymeslower the activation energy of a reaction

16. In an endergonic reaction, the reactants contain less free energy than the products

17. The energy available to do work in a system is calledfree energy

18. What is cellular respiration? • Converting the energy found in food molecules into ATP. The mitochondria are the site for aerobic respiration and the cytoplasm is usually where anaerobic respiration occurs.

19. How do electron acceptors play a role in cellular respiration? • They help to transfer high energy electrons from one system to another resulting in a complex biochemical pathway

20. What is NAD+? • Nicotidamide Adenine Dinucleotide is a co-factor or co-enzyme that helps transfer the energy in electrons from one system to another

21. What is glycolysis? • The breakdown of glucose into two molecules of pyruvic acid (pyruvate)

22. What is the Krebs Cycle? • Described by Hans Krebs, the Citric Acid Cycle or KrebsCycle is a cycle of chemical reactions converting organic molecules into different forms all the while producing high energy cofactors such as NADH and FADH2 and ATP

23. What is the Electron Transport Chain? • Specialize proton pumps (cytochrome proteins) embedded in the mitochondrial membrane are powered by the products of the Krebs Cycle to pump hydrogen ions across the membrane into the outer compartment of the mitochondria. They flow back across through a special protein enzyme (ATP synthase) and oxidatively phosphorylate ADP into ATP

24. What is chemiosmosis?

25. What is fermentation?

26. Fermentation can be described as takes place in the absence of oxygenrecipient of hydrogen atoms is organic moleculeswater is not a by-productdoes NOT involve the Krebs cycle all of the above

27. A common process to all living organisms, aerobic and anaerobic isglycolysisfermentationKrebs cycleElectron transport chain

28. The decarboxylation of pyruvate produces NADHAcetyl CoACo2ATPOnly a, b, & c are correct

29. The coenzyme electron carriers produced in the Krebs cycle arePyruvate and acetyl CoAFADH and NADHNAD and NADH

30. The oxygen used in cellular respiration ultimately ends up asH2O

31. Muscle cells, when anaerobic, producelactate

32. What substance is produced by the oxidation of pyruvate and feeds the Krebs cycle?acetyl CoA

33. What role does oxygen play in oxidative respiration?final electron acceptor in the electron transport chain

34. During the electron transport chain, H+ are pumped out of the cellout of the mitochondrial matrix into the outer compartment of the mitochondria

35. ATP is a molecule containing energy in its phosphate bonds. (7.3 kcal).

36. Because the chemical formation of ATP is driven by a diffusion force similar to osmosis, this process is referred to as chemiosmosis

37. In the absence of oxygen, hydrogen atoms generated by glycolysis are donated to organic molecules in a process called fermentation

38. What are the reactants and products of photosynthesis? • Reactants are carbon dioxide and water • Products are sugar, oxygen, and metabolic water

39. How is light captured by green plants? • Wavelengths of light called photons are absorbed by specific pigments in the leaf. The most abundant is chlorophyll – accessory pigments called carentenoids and xanthophylls absorb what chlorophyll can not and channel the energy to the chlorophyll

40. What is visible light? • That part of the electromagnetic spectrum that we see as white light, which is a blend of all the colors of the rainbow

41. What determines whether an element/compound can absorb/reflect light waves (photons)? • The outermost electrons (valence) of a pigment molecule determines what wavelength will be absorbed

42. Know what happens during photosystem I & II. • Water is split by sunlight and the energy (electron) powers two sets of photosystems that eventually produce ATP and NADPH which will be used in the stroma of the chloroplast for the light –independent reactions

43. Understand the basics behind the Calvin Cycle. • The Calvin cycle, described by Melvin Calvin is otherwise known as the dark reactions of photosynthesis or the light independent reactions. It is where carbon from carbon dioxide of animals is fixed into various organic molecules in a cycle that eventually produces sugar as the product.

44. What type of plants use the C4 pathway and why? • Tropical plants that grow very fast have adopted this more efficient way to fix carbon into sugar. They are able to store excess carbon in bundle sheaths to be used during the dark reactions.

45. What type of plants use the Crassulacean Acid Pathway (CAM)? • Desert plants must use this form of making sugars because the live in hot arid environments. They must open their stomata at night when it’s cooler to take in carbon dioxide so that they do not dessicate.

46. What is the cell cycle? • The lifecycle of a typical cell which involves interphase, mitosis, and cytokinesis. Interphase has three phases, G1, S, and G2.

47. What are the phases of the cell cycle? • Interphase, Mitosis, and cytokinesis

48. What are somatic cells? • Body cells which have a 2N number of chromosomes

49. What cellular division results in an exact copy of DNA in the daughter cells? • mitosis

50. What cellular division results in half the number of chromosomes? • meiosis